Induction of neutralizing antibodies against Tityus serrulatus toxins by immunization with a recombinant nontoxic protein

An immunogenic nontoxic protein (TsNTxP) was purified from the venom of the scorpion Tityus serrulatus (Ts), This peptide is composed of 63 amino acid residues with a high degree of structural homology with the toxins isolate d from Ts. The nucleotide sequence of the gene that encodes TsNTxP was obta ined and also showed a high degree of similarity with genes encoding Tityus toxins [Guatimosim, S.C.F., Prado, V.F., Diniz, C.R., Chavez-Olortegui, C. , Kalapothakis, E., 1999. Molecular cloning and genomic analysis of TsNTxP: an immunogenic protein from Tityus serrulatus scorpion venom, Toxicon 37, 507-517]. In the present study the TsNTxP gene was expressed in E, coli BL2 1DE(3) cells as a fusion protein with maltose-binding protein. The recombin ant protein (TsNTxPrec) was purified by affinity chromatography and used as an immunogen in rabbits. The antigenic specificity of anti-TsNTxPrec antib odies was compared by an enzyme-linked immunosorbent assay using TsNTxP, Ts tPG(50) (the fraction of Ts venom that represents most of the toxicity of t he crude venom) and the crude venom, to coat microtitration plates. Anti-Ts NTxPrec antibodies had a comparable high cross-reactivity for all antigens tested. Concentrations of Ts venom equivalent to 20 LD50 were effectively n eutralized by mi of the anti-TsNTxPrec serum. This result provides basic da ta for the use of such recombinant scorpion protein as an immunogen in the development of antivenoms for clinical use. (C) 1999 Elsevier Science Ltd. All rights reserved.